Problem: Michael is 3 times as old as Ashley and is also 8 years older than Ashley. How old is Michael?
Answer: We can use the given information to write down two equations that describe the ages of Michael and Ashley. Let Michael's current age be $m$ and Ashley's current age be $a$ $m = 3a$ $m = a + 8$ Now we have two independent equations, and we can solve for our two unknowns. One way to solve for $m$ is to solve the second equation for $a$ and substitute that value into the first equation. Solving our second equation for $a$ , we get: $a = m - 8$ . Substituting this into our first equation, we get the equation: $m = 3$ $(m - 8)$ which combines the information about $m$ from both of our original equations. Simplifying the right side of this equation, we get: $m = 3m - 24$ Solving for $m$ , we get: $2 m = 24$ $m = 12$.